The CEO of one of the three biggest boards and one of three people appointed to a panel to consider the future of Test cricket is not really just an opinion.
The reason I can point to 12 y/o articles about it is that it has been a common view for many for a long time that fewer teams should play.

The Ashes will only matter, and therefore make money, while it remains the oldest and biggest of Test's many series. Take away that context and it is an anachronism. That's a weird choice for an Australian cricket administrator to make

Most relevantly, if the Big 3 dont want to support Test cricket outside a limited number of teams, then it will die. Not because it isn't viable, but because you cannot maintain primacy if Test cricket is a secondary priority for the majority of players.
web.archive.org/web/20160401...

That structure hasn't changed since I wrote about it 12 years ago. Most markets don't make money from their games regardless of format. If CA wants to play international cricket, and it is 80% if their remit, then they need to support those teams.
web.archive.org/web/20160401...

Unfortunate but if Pat had taken his it would have ended earlier.

As someone who has watched cricket deal with this for 30 years, US sports are laughably naive about the level of risk and factors that make it worse. Notably low paid or unpaid players but many other things. Play the Game has had a number of good studies on this.

Any optimism I had earlier in the season was tempered by their percentage being about 15th Unsustainable good fortune in close games.

So while I really liked the whole T20 WC and the format delivered in terms of exciting finishes; we didn't commentate the last few (dead) group games, there was the possibility of shenanigans, and there remains a gap between "scheduled if" and "guaranteed" jeopardy that the ICC often misses on.

And while the nominal number of matches between top 8 and top 12 teams is much higher in the format the ICC have used, because Pakistan and Sri Lanka missed out, it ended up being very similar (or exactly the same if SL beat SCO and PAK beat BAN):
16 vs 12 between top 8 teams
23 vs 26 for 8 vs 12

The difference is the ICC went with the "Super 8" to make sure the big teams (actually just India) played more games, and to maximise the biggest match-ups, but it came at a cost to dead rubbers.
The breakdown: 6 completely dead vs none. 17 teams playing a game of no consequence vs just 2.